The jury's out on whether the writer of Why I use 'middle class' as an insult fulfilled the promise made in the headline. But reading between the lines, we can assume that the negative connotations she associates with the term "middle class" may have their origins in the fact that she and her husband "both grew up on council estates" and now they appear to endure the trappings of the so-called middle classes with more than a modicum of guilt.

The lively comments section contained such contributions as: there is "something faintly ridiculous about relatively well off people desperate to wear their working class credentials as a badge of honour", "I think the Queen Mum used 'middle class' as an insult as well" and "Class is increasingly irrelevant - what matters is money".

Writing for The Sunday Times, India Knight noted that "middle class" has morphed from being a simple statement of fact to a descriptor with baggage attached.

In It was nice and cosy in the middle class - until the deniers moved in she says, "The use of the term 'middle class' as an insult has always completely baffled me. In any halfway prosperous country ... anyone who isn't either very poor or lunatically rich is by definition middle class."

Part of the problem stems from the fact that there is little agreement on what constitutes middle class. Exactly what attributes do these people share? According to the conflicted writer of the piece in The Guardian, it might entail having a mortgage, owning a car and taking the children on overseas holidays. Offering a US-based perspective, 9 ways to know if you're middle class says middle class people go on vacation, own their own home, have a secure job and have health insurance.

Are you in the middle class? shares a Canadian viewpoint: "Economists don't really agree on what constitutes a middle class income. We know the upper class is the top 20% of income earners and the lower class are the bottom 20%. Everyone else falls in the middle."

There's a dearth of local information on the subject. "Despite the apparent increase in inequality in the last decades of the 20th century, there was little analysis of class in New Zealand society", says The Encyclopedia of New Zealand which suggests that our multicultural society must bear some of the responsibility. Evidently, New Zealanders are more inclined to think along racial divides than class divides.

A University of Auckland quantitative research report entitled The Influence of Class on Class Perceptions in New Zealand discovered New Zealanders possessed some conflicting opinions on social class: "Data [gathered in 2009] suggests opposing views of New Zealand society in relation to individual class ... broadly speaking, those in the lower and working classes appear to view New Zealand as a class based society, while those of the upper classes do not."

With no universal agreement as to the precise definition of "middle class" and even divided opinion as to whether New Zealand is an especially class-based society, it's perhaps understandable why "middle class" has become a derogatory term. In the absence of a definitive meaning, it can be aimed at almost anyone without fear that the assertion can be disproved.

If "middle class" is an insult then it must be an insult of last resort. It's a nebulous, one-size-fits-all mild term of abuse used by lazy people without the imagination to think of anything truly damning to say about the object of their disapproval.

What do you think are the indicators of middle class? Why do you think is it sometimes used as an insult?

Shelley Bridgeman is a truck-driving, supermarket-going, horse-riding mother-of-one who is still married to her first husband. As a Herald online blogger, she specialises in First World Problems and delves fearlessly into the minutiae of daily life. Twice a week, she shares her perspective on a pressing current issue and invites readers to add their ten cents’ worth to the debate.